Few population-baed investigations have been previously undertaken that examine the association between psychiatric disorders in pregnancy and poor pregnacy outcome. In the past decade, case control studies suggest that schizophrenia is assoicated with decrease prenatal care and poor pregnacy coutcome, but the results have been contradictory. Furthermore, it has been found that 10-20% of pregnant women abuse sustances. The long term consequences of untrated maternal psychiatric illness are potentially grave as the cognitive ans emottional health of the infant are affected. This study will begin to address the gaps in our knowledge of the epidemiology, course and outcome of psychiatric disordes in pregnancy. The soecific aims of this investigation are to:1) examine the rates of psychiatric and substance abuse diagnoses and their comorbidity at the time of delivery as recorded on hospital discharge summary 2) examine the soci-demographic characteristics of the mothers with psychiatric and substance abuse diagnoses at delivery 3) measure the association between maternal psyhiatric diagnoisis and selected poor maternal and fetal outcomes and length of hospital stay. We will conduct a cross sectional epidemiologic study using the California Health Infornmation for Policy Project (CHIPP) data set, which contains material and discharge and birth certificate data for the approximately 600,000 births in California in 1992. Logistic regression models will be used to test for significant associations between demograghic variables and psychiatric diagmoses, as well as psychiatric dignoses and poor pregnancy outsomes while examining the effects of demographic, maternal hypertension and diabetes, parity, and prenatal care.